Prospects of analyzing of nanoparticles in the composition of aerosol by the method of electron microscopy

Abstract

Introduction. Control of distribution of aerosol particle by size in the workplace area is one of the important problems of hygiene. To assess health effect of aerosol particles in workers, it is necessary to improve existing and introduce new methods for analyzing the dispersion and chemical composition of aerosols, including their nanosized constituents.
 Materials and methods. Generated lead oxide nanoparticles with an average diameter of 26.2±12.6 nm were sampled on 47-mm nylon membrane disc filters with a pore size of 0.2 µm and 1.2 µm. The experimental device represented a cascade system consisting of two membrane filters, where the first filter was intended for capturing nanoparticles while the second one was used for establishing the capture efficiency of the first. The sampling time for the cascade systems was 5, 10, 15, 20, 40, and 80 minutes for filters with a pore size of 0.2 µm and 5, 10, 20, and 120 minutes for those with a 1.2 µm pore size; in all cases, the volumetric flow rate was 1.5 L/min. The membrane surface was then analyzed by scanning electron microscopy.
 Results. Lead oxide nanoparticles were found on all filters tested. They were evenly distributed over the entire effective filter area, their number increasing with air sampling duration. No nanoparticles were observed on the second level filters, regardless of the sampling period.
 Limitations. The results cannot be extrapolated to all types of nanoparticles since the capacity of polyamide/nylon filters was studied only with respect to lead oxide nanoparticles.
 Conclusion. The study proved that polyamide/nylon filters with the pore sizes of 0.2 µm and 1.2 µm have a high potential for nanoparticle capture and can be considered as a tool for developing new techniques of studying and controlling harmful factors.